I have a Volvo s60 D5 deisel made in 2006. It's a beautiful car all the toys, fast and comfortable. Unfortunately it has a Particulate filter.
This is an exhaust filter that reduces the emmissions to comply with recent regulations. However, the filter eventually fills up with soot. I get a message on the dashboard "Soot filter full" (odd message considering I didnt put any coal in it). Anyway,once the filter full indicator comes on you need to clear the filter. This is done by driving continuously at minimum revs of 2500 for about 20 minutes. This should burn off the soot.
If this is not done soon enough the filter becomes clogged and may not clear. Then you need a trip to the garage to clean it and the EGR valve (what ever that is). If that is not successfull then a new filter is needed.
Now the bad news: I use a Volvo specialist garage who guarantees to be at least 40% cheaper than a main dealer: Clean only £845. Replace filter and clean £1100
These filters are in most deisel cars made after 2006 and all new. There is no problem if you frequently drive on major roads as the clean phase will be done as soon as needed. Some of us live in large cities where you can drive up to 40 minutes to get on open roads. If you are like me the city dweller,do not get a DPF fitted car. I left mine for just four days (about 40 miles) after the filter full message came on and have just had it cleaned.
Sunday it gets traded in for a petrol engine car.
A long post but it might help someone avoid the problems I have had.